As is well known by those skilled in the art, in providing oil-type circuit-interrupters, it has been common practice to provide interrupter extinguishing grid structures formed by contiguously stacking a plurality of suitably-configured insulating plate elements. As typical of such prior-art structures, reference may be made to U.S. Pat. No. 3,646,296, issued Feb. 29, 1972 to Robert L. Hess and Gerald D. Simmers, and assigned to the assignee of the instant patent application. Such an oil-grid structure provides oil pockets and side lateral venting passages, all having the function of creating turbulence and providing an exhausting lateral venting action to assist in extinguishing the drawn arc, which is established and lengthened within the extinguishing grid structure by the downward opening separating movement of a rod-shaped movable contact away from an upper-disposed stationary finger-type contact structure.
As descriptive of additional prior-art constructions, reference may also be made to U.S. Pat. No. 3,356,811, issued Dec. 5, 1967 to George B. Cushing and Frank L. Reese, and also assigned to the assignee of the present invention. With regard to oil-pumping assemblies, reference may additionally be made to Jawelak et al U.S. Pat. No. 3,819,893, issued July 26, 1972, and Jawelak et al U.S. Pat. No. 3,867,597, issued Feb. 18, 1975.
It is well known in the art to provide oil-grid structures having pairs of lateral venting passages. Consider, for example, U.S. Pat. No. 2,811,614, issued Oct. 29, 1957 to P. L. Taylor et al, in which FIG. 9 of said patent shows lateral venting ports 64 and 65. In addition, reference may be made to U.S. Pat. Nos. 2,545,334 and 2,539,175, both issued to Conrad J. Balentine and showing venting passages 41 in FIG. 3 of Balentine U.S. Pat. No. 2,545,334, and venting passages 44a in FIG. 4 of Balentine U.S. Pat. No. 2,539,175.
Of interest also, in regard to laminated plate structures, encompassed within an outer-disposed insulating cup-shaped casing, for maintaining the plates in a proper position, reference may be had to U.S. Pat. No. 3,819,893, issued June 25, 1974 to Melbourne G. Jawelak et al. In addition, this latter patent, Jawelak et al U.S. Pat. No. 3,819,893 shows an oil-pumping assembly 32, 32' disposed on the inner sides of the grid units 14, 16, as illustrated in FIG. 1 of said patent.